Brain Tsunamis

As their name implies, these waves of depolarization destroy brain function the way their watery counterparts wipe out homes.

The events that occur with major brain injuries and head trauma may be very similar to a rare but devastating ocean-related disaster. The initial trauma is the first insult to the brain, but what happens in the hours and days afterward may be even worse.

Much like the weather-related tsunamis, these large waves of depolarizations spread slowly but persistently throughout the brain, causing widespread brain dysfunction.

Neurological events called “brain tsunamis” occur several days after severe head trauma and may be responsible for inducing brain damage, according to a new study. Preventing these tsunamis or “killer waves” could help patients with severe head trauma avoid further brain damage and possibly retain most of their brain function.

The “brain tsunamis” are actually large population of brain cells that undergo massive depolarizations. Much like the weather-related tsunamis, these large waves of depolarizations spread slowly but persistently throughout the brain, causing widespread brain dysfunction.

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These wave-like depolarizations have been studied in brain trauma patients for decades. But the new research showed for the first time that brain tsunamis are responsible for causing further brain damage in afflicted patients. The brain tsunamis drew the attention of the U.S. military as head injuries became a very common injury among veterans of the Iraq and Afghanistan wars.

The study is a collaboration between Kings College Hospital in London and the University of Cincinnati School of Medicine in Ohio. The researchers followed 103 people across seven different centers worldwide who underwent neurosurgery following major head trauma. Fifty-eight of those patients experienced the “brain tsunami” event, leading to a spread of cell depolarizations within the cortex.

The researchers measured the extent of the depolarizations by placing a linear strip of electrodes on the surface of the brain as the patient underwent neurosurgery. The patients were then followed for the duration of their post-operative care, to see whether the outcome of the neurosurgery was favorable.

The investigators hope that their results may alter the long-term treatment of brain trauma patients in a way that could possibly lead to better outcomes. Previous studies have identified other ways to improve outcomes in humans with brain injury.

In this case, the researchers hope that the spreading cortical deplarizations could somehow be stopped before they start in trauma patients undergoing surgery. So far, however, the investigators have not speculated how that could be achieved.

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“Our ability to monitor and understand what happens in the brain after a severe injury hasn't advanced significantly in decades. The brain is like a black box, but the process of spreading depolarizations now gives us a window into that box,” said principal investigator, Jed Hartings, of the University of Cincinnati College of Medicine.